The following relates generally to wireless communication, and more specifically to timing advance design.
Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, and orthogonal frequency division multiple access (OFDMA) systems. A wireless multiple-access communications system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, which may each be referred to as a user equipment (UE).
In conventional systems, a base station may communicate with UEs in shared or unlicensed radio frequency spectrum band. When communicating in an unlicensed spectrum, there may be a gap between downlink (DL) and uplink (UL) transmissions during which UEs may attempt to reserve the shared spectrum. In some cases, UEs may initiate UL transmissions at different times to account for propagation delay based on geographic distance to a base station.
UL transmissions that are not synchronized in time may increase computational complexity at a base station. Unaligned UL transmissions may also result in interference between UEs. This may result in additional system costs or reduced system throughput.